This invention relates to electrical rotary switches having control knobs positioned in housings.
German patent document DE 28 24 584 A1 discloses a rotary switch of this type, having surrounding contacts in a main body that are contacted by a tap member acting in a radial direction relative to a rotational axis.
This rotary switch is already available in a compact design, however a range of adjustment of a control knob thereof is not sufficiently large to permit sensitive adjustment.
German patent document DE 89 12 785 U1 discloses a tandem potentiometer in which a wiper is coupled via a step-down gear to a drive shaft so that one of the wipers is adjusted by a smaller angle than an angle of movement of the drive shaft. This makes possible a more sensitive adjustment of the potentiometer.
The step-down gear is said to be formed by a planet wheel gear, whereby the wiper referenced above is connected to a planet wheel located between gearing of the drive shaft and a stationary, concentric gear wheel.
Based on the foregoing, it is an object of this invention to develop a rotary switch of the type mentioned in the opening paragraph with which sensitive adjustment can be obtained at reduced construction expenses.